The Atlantic has two articles about longitudinal studies: the Harvard Study of Adult Development, begun in 1937, which followed the lives of Harvard sophomore men for over 70 years to study their physical and mental health and The Longevity Project, begun in 1921, which studied 1,500 children for more than 80 years to determine factors to having a long, healthy life.
What were the outcomes of each study? It appears that divorce puts men at a higher rate for an untimely death.
Harvard: “What allows people to work, and love, as they grow old? Vaillant…had identified seven major factors that predict healthy aging, both physically and psychologically…Employing mature adaptations was one. The others were education, stable marriage, not smoking, not abusing alcohol, some exercise, and healthy weight. Of the 106 Harvard men who had five or six of these factors in their favor at age 50, half ended up at 80 as what Vaillant called ‘happy-well’ and only 7.5 percent as ‘sad-sick.’”
Longevity: “Marriage was health-promoting primarily for men who were well-suited to marriage and had a good marriage. For the rest, there were all kinds of complications…For example, women who got divorced often thrived. Even women who were widowed often did exceptionally well. It often seemed as if women who got rid of their troublesome husbands stayed healthy—most women, it seemed, can rely on their friends and other social ties. Men who got and stayed divorced, on the other hand, were at really high risk for premature mortality. It would have been better had they not married at all.”